Extended range RF-ID transponder.

摘要

An transponder arrangement (10) for use with tyres (20) is described. The arrangement (10) includes an antenna (14) which is mounted about the tyre's(20) perimeter. The antenna (14) preferably has a coupling coil (16) at one end. A transponder (12) is preferably located close to the coupling coil (16) and is preferably loosely coupled to the coupling coil (16). The RF-ID efficiency of the arrangement (10) is generally optimized for this type of application by the long but narrow antenna solution and by the simple fact that coupling an antenna (14) to a transponder (12) amplifies the emission of the transponder's signal relative to the noise, thus improving the signal-to-noise ratio of the RF-ID system. The degree of coupling between the antenna (14) and the transponder (12) is not particularly critical. The antenna (14) acts to extend the reading range for the interrogator (24) to be generally, radially symmetric about the tyre (20). Other arrangements are disclosed. <IMAGE>